I think for me there's 2 levels of eye contact. When you look at the eyes, and then when your pupils look straight into the other pupils. When I look straight into the pupils, it's like I put a fix on them and I get some sort of tunnel vision. Now that I think of it maybe my brain thinks of the reverse, that I'm somehow put on the spot by the other person, and I become anxious. Doesn't happen all the time, but when it happens, it becomes weird.